Means for automatically cutting off the feed-motion of machine-tools



N. J. OLSSON. MEANS FOR AUTOMATICALLY CUTTING OFF THE FEED MOTION OF MACHINE TOOLS. APPLICATION FILED'AUGJI 19TH.

1 ,328,337. Patented Jan. 20, 1920.

W JMC! UNITED STATES PATENT OFFICE.

NILS JOSE]? OLS SON, OF GOTTENBORG, SWEDEN, ASSIGNOR TO AKTIEBOLAGET SVENSKA KULLAGERFABRIKEN, OF GOTTENBORG, SWEDEN, A CORPORATION OF SWEDEN.

MEANS FOR AUTOMATICALLY CUTTING OFF THE FEED-MOTION OF MACHINE-TOOLS.

Specification of Letters Patent.

Application filed August 1, 1918. Serial No. 247,784.

To all 'wkomit may concern:

Be it known that I, NILs J osEr OLssoN, a subject of the King of Sweden, residing at Gottenborg, in the Kingdom of Sweden, have invented certain new and useful Improved Means for Automatically Cutting Off the Feed-Motion of Machine-Tools, of which the following is a specification.

This invention relates to automatically operating devices for cutting off the feed motion of grinding machines and other machine tools when the work reaches its desired ultimate diameter, and more particularly to such devices of that class as are described in my co-pending application for patent Serial No. 241,392 filed June 22, 1918, in which a. pivotally mounted lever bears against the work or against a movable member bearing in turn against the work, said lever being so arranged and so formed at its contact point that it will be locked by,

said engagement until the desired diameter of the work is reached, whereupon the lever will by means of a spring, a weight or the like be brought out of engagement with the work and caused to initiate the cutting off of the feed motion.

In order to render the device more reliable and more durable, that is to render it independent to a larger extent of the wear at the contact point of the lever, the end of the lever bearing against the work or against theintermediate member is formed, according to one embodiment of the invention set forth in myv above said application, as an arc the center of which coincides with the axis of the lever. By so forming the lever the effect of the wear is almost completely eliminated as the are proper contacts with the work or with the intermediate member at the releasing moment only.

Accordin to this invention a still more reliable an durable device of the above said kind is obtained b forming the lever of two separate parts a justably connected with each other, the part bearing" against the work or against the intermediate member having wholly or partly the shape of a circular disk the center of which coincides with the axis of the lever. I

This construction facilitates the obtainment of a correct circular shape of that part of the lever co-acting with the work or with the intermediate member, as the case may be, while at the same time by adjustmg the parts of the lever with relation to each other an unacted on part of the circumference of the disk may always control the cutting off action.

In the accompanying drawing forming part of this invention, Figure 1 is a side elevation of a device constructed according to this invention, part of the device being shown in section. Fig. 2 is a side elevation of a modified lever construction.

Referring to Fig. 1, the numeral 1. indicates a casing inclosing a lever'3, 4, carried by the pivotally mounted shaft 2, one arm 4: of said lever being rigidly attached to said shaft and being formed at its outer end as a hammer. Mounted below said hammer is a contact spring 6 adapted to cooperate with an underlying contact piece 7. The arm 4 is controlled by a spring 8 tending to keep the lever in the posltion in which the hammer of the arm 4 keeps the spring 6, in contact with the fixed contact 7. The hammer of the arm 4 is formed with a hook-sha ed portion 9 adapted, when the arm 4 is li tied up, to be engaged by a pawl 10 for keeping the lever out of operative position, as is shown by dotted lines in Fig. 1.

The arm 3 of the lever B, 4: consists of a circular disk so connected, as by means of a screw connection 24, with the arm 4: that the center of the disk coincides with that of the pivot 2, the arrangement being such that the disk 3 may after the said connection has been released be turned about the pivot 2.

Provided in the circumference of the disk 3 is a recess 23 forming an edge 25 at the circumference of the disk.

The contacts 6 and 7 are intended to be included in the circuit of an apparatus for cutting off the feed motion of the grinding machine'or other machine tool in connection with which the device is intended to be used. Said apparatus may be of any convenient or known type and will not be described as it does not form any. part of this invention. The distance between the contacts 6 and 7 should be so chosen that the tension existing in the said circuit will not be high Patented Jan. 20, 1920.

placed in the longitudinal direction of the lever 3, 4 by means of the set-screw 12.

The apparatus shown in Fig 1 is especially adapted for use in combination with grinding machines for external grinding operations.

When the apparatus is to be used, the lever 3, 4 is locked by means of the pawl 10 in the position shown by dotted lines in Fig. 1 whereupon the casing 1 is so adjusted by means of the screw 12 that the edge 25 of the disk 3 will upon the release of the lever be brought in contact with the circumference of the work beneath the horizontal diameter thereof. The work 26 should be ro tated in the direction of the arrow so as not to tend to press the disk 3 upward.

According as the diameter of the work is reduced during the grinding operation, a successive movement of the lever 8, 4 about the shaft 2 takes place .under the control of the spring 8, and when the desired ultimate diameter of the work has been reached, the circumference of the disk will touch the work and the disk will immediately be free to move under the action of the spring 8.

The spring 8 now swings the released lever .3, 4 so as to cause it to bring about the closing of the contacts 6 and 7 thus closing the circuit controlling the cutting off of the feed motion of the grinding machine.

In the apparatus above described there is no tendency for premature circuit closing inasmuch as the lever 3, 4 is completely out of engagement with the contact spring 6 before the edge 25 has passed the central position. The normally existing distance between the contacts 6 and 7 which is large enough to prevent the formation .of sparks will thus be constant until the moment at which the closing is to take place.

When the edge 25 has been worn to such a degree that required length of the lever arm co-acting with the work, that is the disk 3, is no longer maintained it is only necessary for restoring the original length of the said arm (that is the disk 3) to release the screw connection 24 and turn the disk 3 through a small angle relatively to the lever arm 4. When the disk 3 has been worn to such an extent that no decided edge 25 at all will remain, it is suitable to so complete the recess 23 that a new edge corresponding to that shown in Fig. 1, will be obtained. In order to avoid this I may originally form the disk 3 with a set of recesses at the circumference thereof.

Such a form is shown in Fig. 2. The disk 3 is provided with six recesses 23 forming a corresponding number of teeth 27, each having an edge The circumferential or top surfaces of the teeth 27 form part of one neaassv and the same circular cylindrical surface the axis of which coincides with that of the shaft 2. NVhen any tooth has been worn to such an extent that no part of its original top surface remains it is only necessary to.

turn the disk 3 on the shaft 2 through an angle corresponding to the distance between two adjacent teeth, thereby restoring the original length of the part of the 'lever 3, 4 represented by the disk3.

In my divisional application, Serial No. 319,424, filed August 23, 1919, I describe and claim a structure having teeth of different radii, thus enabling a single disk to be used for different diameters of work.

It is obvious that the details of the device may be modified in several respects without departing from the principle of the invention. 1

\Vhat I claim is 1. Inmachin'e tools an arrangement for automatically cutting off the feed motion of the machine when the work has reached its desired ultimate size, comprising a pivotally mounted lever, a shaft carrying said lever, said lever consisting of two parts adjustably connected with each other one of said parts being formed as a disk the center of which coincides with the center of said shaft, said disk being so arranged and formed as to be locked by the work during the operation thereof and be released for initiating the said cutting ofl action when the work reaches its desired ultimate size.

2. In machine tools an arrangement for automatically cutting off the feed motion of the machine when the work has reached its desired ultimate size, comprising a pivotally mounted lever, a shaft carrying said lever, said lever consisting of two parts adjustably connected with each other, one of said parts being formed as a toothed disk, the top surface of each of the teeth of said disk forming part of a cylindrical surface the center of which coincides with the center of said shaft. i

3. In machine tools an arrangement for automatically cutting off the feed motion of the machine when the work has reached its desired ultimate'size, comprising a pivotally mounted lever, a shaft carrying said lever, said lever consisting of two parts adjustably connected with each other, one of said parts being formed as a toothed disk each tooth of said disk forming an edge at the circumference of the disk, the top surface of each tooth forming part of a cylindrical surface the center of which coincides with the center of the said shaft.

In testimony whereof I affix my signature.

NILS JOSEF OLSSON 

